Treating processes sulfuric acid

Seaweeds. The eadiest successful manufacture of iodine started in 1817 using certain varieties of seaweeds. The seaweed was dried, burned, and the ash lixiviated to obtain iodine and potassium and sodium salts. The first process used was known as the kelp, or native, process. The name kelp, initially apphed to the ash of the seaweed, has been extended to include the seaweed itself. About 20 t of fresh seaweed was used to produce 5 t of air-dried product containing a mean of 0.38 wt % iodine in the form of iodides of alkah metals. The ash obtained after burning the dried seaweed contains about 1.5 wt % iodine. Chemical separation of the iodine was performed by lixiviation of the burned kelp, followed by soHd-Hquid separation and water evaporation. After separating sodium and potassium chloride, and sodium carbonate, the mother Hquor containing iodine as iodide was treated with sulfuric acid and manganese dioxide to oxidize the iodide to free iodine, which was sublimed and condensed in earthenware pipes (57). 

Sulfate Process. In the sulfate process (Fig. 2), ihnenite ore is treated with sulfuric acid at 150—180°C ... 

Sodium chromate can be converted to the dichromate by a continuous process treating with sulfuric acid, carbon dioxide, or a combination of these two (Fig. 2). Evaporation of the sodium dichromate Hquor causes the precipitation of sodium sulfate and/or sodium bicarbonate, and these compounds are removed before the final sodium dichromate crystallization. The recovered sodium sulfate may be used for other purposes, and the sodium bicarbonate can replace some of the soda ash used for the roasting operation (76). The dichromate mother Hquor may be returned to the evaporators, used to adjust the pH of the leach, or marketed, usually as 69% sodium dichromate solution. 

Frequently kaolin clay is used for a raw material. In one of the older processes kaolin is treated with sulfuric acid at elevated temperature and subsequently washed to remove Hberated alumina and alkaUes. Kaolin can also serve as a raw material for preparing a number of synthetic zeofltes (21). 

One of the most important appHcations of this process is that of methyl methacrylate manufacture. In this process (81), acetone cyanohydrin is treated with sulfuric acid at 100°C, affording the corresponding methacrylamide sulfate which is esterified with methanol. After purification, methyl methacrylate (99.8% purity) is obtained in a yield of ca 85%. 

Phosphoric acid made by the wet process, in which phosphate rock is treated with sulfuric acid, is highly inert toward lead in any concentration for temperatures up to 150°C, However, in the dry process, where hydrogen phosphate (H3PO4) is made directly from phosphorus or phosphorus pentoxide (P2OS), a chemical reaction with lead occurs. 

Preparation. A continuous process is described in Ref 26 for its prepn from nitric acid and acetylene. Other prepns on both lab and industrial scales are by the action on Tetranitro-methane (TeNMe) of K hydroxide in aq glycerol (Ref 16), aq HOCHjSOaNa, or 30% aq H peroxide (Ref 19a) to give the K salt which is treated with sulfuric acid (Ref 16), syrupy phosphoric acid (Ref 20), or best by passing gaseous HC1 thru a suspension of the K salt in anhyd eth (Ref 19a). It has also been prepd by the action of nitric acid on malonamide,... 

When primary nitro compounds are treated with sulfuric acid without previous conversion to the conjugate bases, they give carboxylic acids. Hydroxamic acids are intermediates and can be isolated, so that this is also a method for preparing them. Both the Nef reaction and the hydroxamic acid process involve the aci form the difference in products arises from higher acidity, for example, a difference in sulfuric acid concentration from 2 to 15.5 M changes the product from the aldehyde to the hydroxamic acid. The mechanism of the hydroxamic acid reaction is not known with certainty, but if higher acidity is required, it may be that the protonated aci form of the nitro compound is further protonated. 

For Ti02 and Z1O2, it is well known that sulfation induces a strong increase of acidity [17] and the participation of an add mechanism could then account for this promotion of activity. This mechamsm can be described as a bifunctional process oxidation of NO to NO on Cu sites, and nitration of a product of the oxidation of decane on the acid fiinction(8). The preparation of the catalyst must have a great influence on the activity. This has been shown by the comparison of three Cu/TiC catalysts prepared in different conditions one in which titania is first treated with sulfuric acid, then by Cu acetate (denominated Cu 04/Ti02, containing 0.S wt% Cu, 0.6 wt% S), one in which Cu is... 

However, inorganic acids are used in various processes to treat unfinished petroleum products such as gasoline and kerosene, and lubricating oil stocks are treated with sulfuric acid for improvement of color, odor, and other properties. 

Cationic polymerization is, of course, an inter-molecular electrophilic addition process. Intramolecular electrophilic addition involving two double bonds in the same molecule may be used to generate a cyclic system. Thus, the trienone shown is converted into a mixture of cyclic products when treated with sulfuric acid. 

Cadmium is obtained as a byproduct in zinc recovery processes. The metal volatdizes during roasting of zinc concentrates and collected as dust or fume in bag houses or electrostatic precipitators. The dusts are mixed with coal (or coke) and zinc chloride and calcined. The cadmium chloride formed volatihzes upon calcination and thus separates out from zinc. The chloride then is treated with sulfuric acid in the presence of an oxidizing agent. This converts lead, present as impurity in cadmium ore, to lead sulfate which precipitates out. Cadmium is finally separated from copper by the addition of zinc dust and... 

Sodium carbonate was made historically by the Leblanc process. The first commercial production was carried out by the Leblanc process. In this process, sodium chloride was treated with sulfuric acid to produce sodium sulfate and hydrochloric acid. Heating the sodium sulfate with coal and limestone produced a black ash that contained sodium carbonate, calcium sulfide, unreacted coal, and calcium carbonate. Sodium carbonate was separated from the black ash by leaching with water. The overall reaction is as follows ... 

Uranium is best known as a fuel for nuclear power plants. To prepare this fuel, uranium ores are processed to extract and enrich the uranium. The process begins by mining uranium-rich ores and then crushing the rock. The ore is mixed with water and thickened to form a slurry. The slurry is treated with sulfuric acid and the product reacted with amines in a series of reactions to give ammonium diuranate, (NH4)2U20 . Ammonium diuranate is heated to yield an enriched uranium oxide solid known as yellow cake. Yellow cake contains from 70—90% U3Og in the form of a mixture of U02 and U03. The yellow cake is then shipped to a conversion plant where it can be enriched. 

In the process (Fig. 1), the ore is ground and mixed with ground limestone and soda ash, and roasted at approximately 1200°C in an oxidizing atmosphere. The sintered mass is crushed and leached with hot water to separate the soluble sodium chromate. The solution is treated with sulfuric acid to convert the sodium chromate to sodium dichromate plus sodium sulfate. Some of the sodium sulfate crystallizes in the anhydrous state from the hot solution during acidification as well as in the evaporators during concentration of the dichromate solution. From the evaporator, the hot, sat-... 

The yield of the main product (I) can be increased by the catalytic regrouping of the products of the hydrolytic condensation of ethylethox-ysilanes. For this purpose, the products of hydrolytic condensation are treated with sulfuric acid or various types of clay (kil, askanite, bentonite) activated with mineral acids. It is accompanied by the following processes ... 

Friedel-Crafts alkylation processes were traditionally operated at 65-70°C with AICI3 and at 40-60°C with HF. A variety of solid acid catalysts have been developed at the laboratory level, mainly based on zeolites, heteropolyacids or sulfated zirconia (zirconia treated with sulfuric acid). The most recent industrial achievement is the Detal process (UOP-CEPSA) which is based on silica-alumina impregnated with HF. The selectivity towards linear alkylbenzenes exceeds 95%. The cymene processes use AICI3 in the liquid phase or supported phosphoric acid as catalysts. 

The supposition that a carbonium ion is formed as an intermediate in these reactions is still further supported by the observation that when ferZ-butyl esters are treated with sulfuric acid in dioxane solution, isobutylene is formed, and the process is completely reversible.15 Similarly, the reaction of tert-butyl benzqate with acetic acid in the presence of p-toluenesulfonic acid gave a small amount of isobutylene.16... 

Derivation From ilmenite or rutile. (1) Ilmenite is treated with sulfuric acid and the titanium sulfate further processed. The product is primarily the anatase form. (2) Rutile is chlorinated and the titanium tetrachloride converted to the rutile form by vapor-phase oxidation. Papermakers are using this form to an increasing extent in preference to the anatase form. 

Synthetic or manufactured sodium sulfate was originally produced in Canada in the late 1800s [41], as a by-product of the Mannheim furnace method for the production of hydrochloric acid [42]. This process consists of an acidulation step, where sodium chloride is treated with sulfuric acid at high temperatures, followed by a purification step where the crude sodium sulfate is recrystallized from water (Eqs. 6.7 and 6.8). 

The process is simple and requires little energy. Low-grade ore is first treated with sulfuric acid to stimulate the growth of bacteria. The microbes process the ore and release copper ions into solution. The metal is then extracted from the solution. 

The basic solution in water containing NaCo(CO)4 is treated with sulfuric acid in the presence of syngas, and HCo(CO)4 is regenerated. This can be extracted from water into the substrate, alkene, and is returned to the reactor. Compared with other schemes (former processes of BASF, Ruhrchemie) the elegant detail of the Kuhlmann process is that the cobalt catalyst is not decomposed via (partial) oxidation but is left in the system as the tetracarbonylcobaltate. 

An unexpected transformation, the exclusive formation of ethyl 2,2,4-trimethyl-3-oxovalerate, taking place via ring scission with the participation of solvent ethanol, was observed on Ni-P foil prepared by electrolytic reduction. After preparation this foil was treated with sulfuric acid to dissolve the Cu plate used as substrate to deposit the amorphous Ni-P foil. We attribute this unusual transformation to acidic centres of the catalyst formed during the latter treatment. In an independent experiment, 1 was reacted without any catalyst in 1 M ethanolic hydrochloric acid at 398 K. The ring-opened ketoester was the only product formed, indicating that the transformation is an acid-catalysed process. The mechanism proposed to account for the selective ring-opening is to be seen in Fig. 2. 

Sodium fluoride occurs naturally as the mineral villiau-mite, although the compound is not produced commercially from that source. Some sodium fluoride is obtained as a byproduct of the manufacture of phosphate fertilizers. In that process, apatite (a form of calcium phosphate that also contains fluorides and/or chlorides) is crushed and treated with sulfuric acid (H2S04). The products of that reaction include phosphoric acid (H3P04), calcium sulfate (CaS04),... 

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